North and south celestial poles

North and South Celestial Poles
The north ands south pivots points around which the sky appears to rotate.
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In the celestial coordinate system the North and South Celestial Poles are determined by projecting the rotation axis of the Earth to intersect the celestial sphere, which in turn defines a Celestial Equator.

Now for some reference makers: The stars rotate around the North and South Celestial Poles. These are the points in the sky directly above the geographic north and south pole, respectively.

The projection onto the sky of the Earth's axis of rotation results in two notable points at opposite directions: the north and south celestial poles. Because of precession, these points trace out circles on the sky.

The upper meridian passing through the north and south celestial poles, and the observer's zenith. This view is looking from the south towards the north for an observer in the Northern Hemisphere.

Celestial pole
the north and south celestial poles are points on the celestial sphere where earths axis of rotation intersects the celestial sphere.

Just like latitude, declination is measured in units of degrees. The two extremes are at the North and South Celestial poles: +90º to -90º respectively (or you could say 90º N and 90º S).

Celestial equator
The projection of Earth's equator into space; also a line in the sky midway between the North and South Celestial Poles. The celestial equator is the line of zero declination in the equatorial co-ordinate system.

colure: (archaic) a great circle on the celestial sphere that passes through the north and south celestial poles. See also equinoctial colure.

Meridian - The great circle passing through an observer's zenith and the north and south celestial poles
Mesopause - The upper boundary of the mesosphere layer of the atmosphere of a planet ...

The celestial equator is defined as being at declination zero (0) degrees; the north and south celestial poles are defined as being at +90 and -90 degrees, respectively.

If you draw an hour circle -- a circle at the hour angle passing through the north and south celestial poles -- you will find the object 16 degrees north of the intersection of this hour circle and the celestial equator.

Celestial poles Points on the celestial sphere directly above the Earth's poles about which all the stars seem to rotate; known as the north and south celestial poles (NCP and SCP).

A coordinate system similar to Earth's latitude and longitude used to locate planets, stars, star clusters, nebulae and galaxies. The celestial sphere is centered on Earth, and it includes the celestial equator, the north and south celestial poles, ...

The projection of the Earth's equator onto the celestial sphere is called the celestial equator. Similarly, projecting the geographic poles onto the celestial sphere defines the north and south celestial poles.

The celestial poles are also the poles of the celestial equatorial coordinate system, meaning they have declinations of +90 degrees and -90 degrees (for the north and south celestial poles, respectively).

Midway between the north and south celestial poles lies the celestial equator, representing the intersection of Earth's equatorial plane with the celestial sphere. These parts of the celestial sphere are marked on Figure 1.7.

See also: Celestial sphere, Sky, Earth, Time, South celestial pole